News / Science & Technology

Research Suggests Prehistoric Man First Influenced Climate Change

Early farmers' use of controlled forest burns, like this one in current-day Uganda, could have begun releasing climate changing gases into the atmosphere 8,000 years ago.
Early farmers' use of controlled forest burns, like this one in current-day Uganda, could have begun releasing climate changing gases into the atmosphere 8,000 years ago.

There is new evidence supporting a controversial theory that humans began changing the earth's climate with the development of agriculture some 8,000 years ago.

In an article published in the journal Nature, researchers studying the theory say new data indicate that enormous amounts of earth-warming greenhouse gases released into the atmosphere by early farming activities helped ward off an impending ice age, and fostered the planet’s current relatively warm, stable climate.  

A more commonly accepted theory suggests that man’s first major influence on the earth’s climate began in the 18th century, at the dawn of the industrial age.   

Scientists say the new findings indicate that the earth was spared from another long deep freeze after the last Ice Age ended 11,000 years ago because of an unusual rise in atmospheric carbon dioxide and methane gas levels starting about 3,000 years later.  

The increase coincided with the advent of farming practices - including the clearing and burning of forests, and maintaining large herds of livestock - that released more of those heat-trapping gases into the atmosphere.

Prehistoric climate expert William Ruddiman of the University of Virginia first proposed the theory in 2003. He said the new findings supporting his hypothesis will be published in a series of papers later this year in a special issue of the journal The Holocene.

Critics of the theory say human populations 8,000 years ago were too small to produce enough greenhouse gases to influence global climate change. And they suggest that other causes, including changes in the earth's orbit and a variety of natural events, could explain the unusual rise in greenhouse gases.

Greenhouse gases are man-made and naturally-occurring gases that trap solar heat in the earth’s atmosphere.

Most scientists now believe that modern man’s burning of fossil fuels and the clearing of forests over the past two centuries have intensified the so-called "Greenhouse Effect" and have caused a gradual warming of the earth's climate.

You May Like

Video Genome Initiative Urgently Works to Freeze DNA Before Species Go Extinct

Smithsonian senior research botanist Vicki Funk says ultimate goal is 'trying to get one-half of the diversity of plant life on Earth at the genus level in two years' More

Video Russia Accused of Abusing Interpol to Pursue Opponents

Report from member of British think tank says Russian extradition requests keep targets from traveling More

US Lawmakers Weigh Turkish Anti-terror Moves

Turkey’s two-pronged campaign against Islamic State militants, Kurdish PKK forces provokes mixed reactions on Capitol Hill More

This forum has been closed.
Comments
     
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Russia Accused of Abusing Interpol to Pursue Opponentsi
X
Henry Ridgwell
July 28, 2015 9:53 PM
A British pro-democracy group has accused Russia of abusing the global law enforcement agency Interpol by requesting the arrest and extradition of political opponents. A new report by the group notes such requests can mean the accused are unable to travel and are often unable to open bank accounts. VOA's Henry Ridgwell reports.
Video

Video Russia Accused of Abusing Interpol to Pursue Opponents

A British pro-democracy group has accused Russia of abusing the global law enforcement agency Interpol by requesting the arrest and extradition of political opponents. A new report by the group notes such requests can mean the accused are unable to travel and are often unable to open bank accounts. VOA's Henry Ridgwell reports.
Video

Video Genome Initiative Urgently Moves to Freeze DNA Before Species Go Extinct

Earth is in the midst of its sixth mass extinction. The last such event was caused by an asteroid 66 million years ago. It killed off the dinosaurs and practically everything else. So scientists are in a race against time to classify the estimated 11 million species alive today. So far only 2 million are described by science, and researchers are worried many will disappear before they even have a name. VOA’s Rosanne Skirble reports.
Video

Video Scientists: One-Dose Malaria Cure is Possible

Scientists have long been trying to develop an effective protection and cure for malaria - one of the deadliest diseases that affects people in tropical areas, especially children. As the World Health Organization announces plans to begin clinical trials of a promising new vaccine, scientists in South Africa report that they too are at an important threshold. George Putic reports, they are testing a compound that could be a single-dose cure for malaria.
Video

Video Special Olympics Athletes Meet International Friends

The Special Olympics are underway in Los Angeles, California, with athletes from 165 countries participating in an event that gives people with intellectual disabilities the chance to take part in an international competition. VOA's Mike O'Sullivan reports that for athletes and their families, it's also an opportunity to make new friends in an international setting.
Video

Video 'New York' Magazine Features 35 Cosby Accusers

The latest issue of 'New York' magazine features 35 women who say they were drugged and raped by film and television celebrity Bill Cosby. The women are aged from 44 to 80 and come from different walks of life and races. The magazine interviewed each of them separately, but Zlatica Hoke reports their stories are similar.
Video

Video US Calls Fight Against Human Trafficking a Must Win

The United States is promising not to give up its fight against what Secretary of State John Kerry calls the “scourge” of modern slavery. Officials released the country’s annual human trafficking report Monday – a report that’s being met with some criticism. VOA’s National Security correspondent Jeff Seldin has more from the State Department.
Video

Video Iran Nuclear Pact Wins Few New US Congressional Backers

Later this week, President Barack Obama returns from a trip to Africa to confront a U.S. Congress roiled by the nuclear accord with Iran, an agreement that has received the blessing of the U.N. Security Council. Days of intensive lobbying and testimony by top administration officials have won few new congressional supporters of the pact. VOA’s Michael Bowman reports.
Video

Video Washington DC Underground Streetcar Station to Become Arts Venue

Abandoned more than 50 years ago, the underground streetcar station in Washington D.C.’s historic DuPont Circle district is about to be reborn. The plan calls for turning the spacious underground platforms - once meant to be a transportation hub, - into a unique space for art exhibitions, presentations, concerts and even a film set. Roman Mamonov has more from beneath the streets of the U.S. capital. Joy Wagner narrates his report.
Video

Video Europe’s Twin Crises Collide in Greece as Migrant Numbers Soar

Greece has replaced Italy as the main gateway for migrants into Europe, with more than 100,000 arrivals in the first six months of 2015. Many want to move further into Europe and escape Greece’s economic crisis, but they face widespread dangers on the journey overland through the Balkans. VOA's Henry Ridgwell reports.
Video

Video Stink Intensifies as Lebanon’s Trash Crisis Continues

After the closure of a major rubbish dump a week ago, the streets of Beirut are filling up with trash. Having failed to draw up a plan B, politicians are struggling to deal with the problem. John Owens has more for VOA from Beirut.
Video

Video Paris Rolls Out Blueprint to Fight Climate Change

A U.N. climate conference in December aims to produce an ambitious agreement to fight heat-trapping greenhouse gases. But many local governments are not waiting, and have drafted their own climate action plans. That’s the case with Paris — which is getting special attention, since it’s hosting the climate summit. Lisa Bryant takes a look for VOA at the transformation of the French capital into an eco-city.
Video

Video Racially Diverse Spider-Man Takes Center Stage

Whether it’s in a comic book or on the big screen, fans have always known the man behind the Spider-Man mask as Peter Parker. But that is changing, at least in the comic book world. Marvel Comics announced that a character called Miles Morales will replace Peter Parker as Spider-Man in a new comic book series. He is half Latino, half African American, and he is quite popular among comic book fans. Correspondent Elizabeth Lee reports from Los Angeles.
Video

Video Critics of Japan Defense Policy Focus on Okinawa

In Okinawa, many locals have long complained that Tokyo places an unfair burden on the tiny island by locating most of Japan's U.S. military bases there. As Japan's government moves toward strengthening and expanding the country's defense policies, opponents of those plans are joining local protesters in Okinawa, voicing concern about where the country is headed. VOA’s Brian Padden reports from Okinawa.
Video

Video IS Uses Chemical Weapons in Syrian Attack

Islamic State militants have added a new weapon in their arsenal of fear: chemical weapons. VOA Kurdish service reporter Zana Omer was on the scene within hours of a recent attack in Hasakah, Syria, and has details of the subsequent investigation, in this report narrated by Miguel Amaya.
Video

Video Historic Symbol Is Theme of Vibrant New Show

A new exhibit in Washington is paying tribute to the American flag with a wide and eclectic selection of artwork that uses the historic symbol as its central theme. VOA’s Julie Taboh was at the DC Chamber of Commerce for the show’s opening.

VOA Blogs